This invention refers to a method of welding workpieces, such as metallic conductors or metal coated workpieces, to a slotted workpiece. Specifically, the invention concerns the welding of electrical coil wires of a direct current motor armature to respective commutator segments or slots using high frequency vibratory energy. Apparatus for performing such welding is described in U.S. Pat. No. 3,791,569, issued Feb 12, 1974 to Bruce L. Mims, entitled "Vibratory Welding Apparatus" and U.S. Pat. No. 3,848,792 issued Nov. 19, 1974 to Bruce L. Mims entitled "Vibratory Welding Apparatus," which patents are incorporated herein by reference.